N=8;
TM=dftmtx(N)
RTM=zeros(N,N);
for n=1:N
    for k=1:N
        RTM(n,k)=1/sqrt(N)*exp(-i*2*pi/N*(n-1)*(k-1));
    end
end
RTM
xn=[1, 2, 3, 4, 5, 6, 7, 8]
xk1=TM*transpose(xn)
xk2=fft(xn)

%dokaz ortonormality
RTM*ctranspose(RTM)